The one thing not ordinary about high school student Ryouta is that he has an aspiring manga artist for an older sister. She is so dedicated to her drawing that, despite being 21, she's never really been in a romantic situation. Unfortunately, when she gets her first real job, it's to write an erotic manga. Desperately, she enlists the reluctant Ryouta's help, as a 'model', to figure out how exactly to draw this sort of manga.

The girl, Mana, has no problem with seeing the scenes she plays with her brother as nothing but a hollow reference for her works.... But she fails to realize that her brother seems to become more and more flustered with each 'live performance'.

Every mangaka has no life experience, especially when it comes to love. Every mangaka needs people to act out the images in the manga because they have no imagination. Is there so little creativity in Japan that mangakas have to write about being a mangaka? And why is it always an attractive, female mangaka that has zero life experience? Series like these have no plot and zero entertainment value unless you have incest fantasies. Just plain stupid. Everyone in Japan wants to screw their sister. I feel bad for those poor girls lol